Method for the improvement of radiological images in the course of an angiography

Abstract

A method if shown for obtaining improved digital radiological images during a digital subtraction angiography (DSA) intervention, carried out by the introduction of a contrast medium consisting of CO2 or other fluid in an examination zone (Z) of a human or animal body, and the creation of digital radiological images (IMC 1 , IMC 2 , IMC 3 IMCn) of the examination zone (Z) at the time of contrast medium input. A mask image (IMM 1 , IMM 2 , IMM 3 IMMn) of the same zone (Z) is subtracted from each image (IMC 1 , IMC 2 , IMC 3 IMCn) with contrast medium and thus produce a series of “clean” digital radiological images (IMP 1 , IMP 2 , IMP 3 IMPn) with limited noise. According to the method, each mask image (IMM 1 , IMM 2 , IMM 3 IMMn) consists of the image with contrast (IMC ( 2 - 1 ), IMC ( 3 - 1 ) IMC (n- 1 )) immediately preceding the image with contrast currently obtained or by weighted combination thereof.

The invention claimed is: 
     
       1. A method for the improvement of radiological images in the course of an angiography exam, comprising introducing a fluid contrast medium in an examination zone (Z) of a human or animal body, obtaining digital radiological images (IMC 1 , IMC 2 , IMC 3  . . . IMCn) of the examination zone (Z) when the contrast medium is introduced, subtracting from each image (IMC 1 , IMC 2 , IMC 3  . . . IMCn) with contrast medium a mask image (IMM 1 , IMM 2 , IMM 3  . . . IMMn) of the same zone (Z), and thereby producing a series of clean digital radiological images (IMM 1 , IMM 2 , IMM 3  . . . IMMn) free of noise, wherein
 each mask image (IMM 1 , IMM 2 , IMM 3  . . . IMMn) consists of at least one image with contrast (IMC ( 2 - 1 ), IMC ( 3 - 1 ) . . . IMC (n- 1 )) chosen from at least one of the images prior to the image with contrast currently obtained, the method further comprising:
 a) obtaining a mask image (IMM 1 ), before entering the contrast medium; 
 b) obtaining an image with contrast medium (IMC 1 ); 
 c) subtracting the mask image (IMM 1 ) from the image with contrast medium (IMC 1 ), thereby obtaining a first clean image (IMP 1 ); 
 d) obtaining a new image with contrast medium (IMC 2 ); 
 e) obtaining a new mask image (IMM 2 , IMM 3  . . . IMMn) consisting of the image with contrast medium (IMC ( 2 - 1 ), IMC ( 3 - 1 ) . . . IMC (n- 1 )) immediately preceding the image with contrast medium (IMC 2 , IMC 3  . . . IMCn) currently obtained; 
 f) subtracting from the image with contrast medium (IMC 2 , IMC 3  . . . IMCn), of the respective mask image (IMM 2 , IMM 3  . . . IMMn) constituted by the previous radiological image with contrast medium (IMC ( 2 - 1 ), IMC ( 3 - 1 ) . . . IMC (n- 1 )), thereby obtaining a corresponding clean radiological image (IMP 2 , IMP 3  . . . IMPn); 
 g) repeating steps b, c, d, and until an end of the exam. 
 
 
     
     
       2. The method according to  claim 1 , wherein said digital radiological images (IMC 1 , IMC 2 , IMC 3  . . . IMCn) are obtained with an imaging process starting from a representation of the examination zone (Z) produced by the X radiation that passes through it and detected by suitable sensitive detection means ( 9 ). 
     
     
       3. The method according to  claim 1 , wherein said contrast medium is constituted by CO2. 
     
     
       4. The method according to  claim 1 , wherein said subtraction is carried out by means of suitable algorithms suitable for subtracting the logical states that make up the digital mask images (IMM 1 , IMM 2 , IMM 3  . . . IMMn) from the corresponding logical states that make up the digital images with contrast (IMC 1 , IMC 2 , IMC 3  . . . IMCn). 
     
     
       5. The method according to  claim 1 , wherein two or more of the clean images (IMP 1 , IMP 2 , IMP 3  . . . IMPn) are superimposed on each other to obtain an angiogram (A 1 , A 2 ) with a more complete representation of the examination zone (Z), including multiple immissions of contrast medium. 
     
     
       6. The method according to  claim 1 , wherein two or more angiograms (A 1 , A 2 ) are combined and joined to obtain the image of an examination zone (Z) plus extended. 
     
     
       7. An apparatus comprising: at least one processor and at least one memory including a computer program, where the at least one memory and the computer program are configured, with the at least one processor, to cause the apparatus to carry out the method of  claim 1 . 
     
     
       8. The apparatus according to  claim 7 , configured to superimpose two or more of the clean images (IMP 1 , IMP 2 , IMP 3  . . . IMPn) together, to obtain an angiogram (A 1 , A 2 ) with a more complete representation of the zone of examination (Z), including multiple immissions of contrast medium. 
     
     
       9. The apparatus according to  claim 7 , configured to approach and join two or more angiograms (A 1 , A 2 ) for obtaining the image of a larger zone of examination (Z). 
     
     
       10. A non-transitory computer readable medium having computer program code stored thereon for execution of the method of  claim 1  by a signal processor. 
     
     
       11. A method for the improvement of radiological images in the course of an angiography exam, comprising introducing a fluid contrast medium in an examination zone (Z) of a human or animal body, obtaining digital radiological images (IMC 1 , IMC 2 , IMC 3  . . . IMCn) of the examination zone (Z) when the contrast medium is introduced, subtracting from each image (IMC 1 , IMC 2 , IMC 3  . . . IMCn) with contrast medium a mask image (IMM 1 , IMM 2 , IMM 3  IMMn) of the same zone (Z), and thereby producing a series of clean digital radiological images (IMM 1 , IMM 2 , IMM 3  . . . IMMn) free of noise, wherein each mask image (IMM 1 , IMM 2 , IMM 3  . . . IMMn) consists of at least one image with contrast (IMC ( 2 - 1 ), IMC ( 3 - 1 ) . . . IMC (n- 1 )) chosen from at least one of the images prior to the image with contrast currently obtained, the method further comprising:
 a) obtaining a mask image (IMM 1 ), before entering the contrast medium; 
 b) obtaining an image with contrast medium (IMC 1 ); 
 c) subtracting the mask image (IMM 1 ) from the image with contrast medium ((IMC 1 ), thereby obtaining a first clean image (IMP 1 ); 
 d) obtaining a new image with contrast medium (IMC 2 ); 
 e) obtaining a new mask image (IMM 2 , IMM 3  . . . IMMn) consisting of a weighted average of at least two images with contrast medium previous to the image with contrast medium (IMC 2 , IMC 3  . . . IMCn) currently obtained; 
 f) subtracting from the image with contrast medium (IMC 2 , IMC 3  . . . IMCn), of said new mask image (IMM 2 , IMM 3  . . . IMMn), thereby obtaining a corresponding clean radiological image (IMP 2 , IMP 3  . . . IMPn); 
 g) repeating steps b, c, d, and until an end of the exam. 
 
     
     
       12. An apparatus comprising: at least one processor and at least one memory including a computer program, where the at least one memory and the computer program are configured, with the at least one processor, to cause the apparatus to carry out the method of  claim 3 . 
     
     
       13. The apparatus according to  claim 12 , configured to superimpose two or more of the clean images (IMP 1 , IMP 2 , IMP 3  . . . IMPn) together, to obtain an angiogram (A 1 , A 2 ) with a more complete representation of the zone of examination (Z), including multiple immissions of contrast medium. 
     
     
       14. The apparatus according to  claim 12 , configured to approach and join two or more angiograms (A 1 , A 2 ) for obtaining the image of a larger zone of examination (Z). 
     
     
       15. A non-transitory computer readable medium having computer program code stored thereon for execution of the method of  claim 11  by a signal processor. 
     
     
       16. A method for the improvement of radiological images in the course of an angiography exam, comprising introducing a fluid contrast medium in an examination zone (Z) of a human or animal body, obtaining digital radiological images (IMC 1 , IMC 2 , IMC 3  . . . IMCn) of the examination zone (Z) when the contrast medium is introduced, subtracting from each image (IMC 1 , IMC 2 , IMC 3  . . . IMCn) with contrast medium a mask image (IMM 1 , IMM 2 , IMM 3  . . . IMMn) of the same zone (Z), and thereby producing a series of clean digital radiological images (IMM 1 , IMM 2 , IMM 3  . . . IMMn) free of noise, wherein
 each mask image (IMM 1 , IMM 2 , IMM 3  . . . IMMn) consists of at least one image with contrast (IMC ( 2 - 1 ), IMC ( 3 - 1 ) . . . IMC (n- 1 )) chosen from at least one of the images prior to the image with contrast currently obtained, the method further comprising defining a depth parameter s, based on said parameter, obtaining clean weighted images (IMPPn), in which each pixel is chosen from equivalent pixels of a number s of clean images (IMPn- 1 , IMPn- 2  . . . IMPn-s); a definition of each pixel of each clean weighted image (IPMPn) consisting in a choice, among s pixels of the previous clean images, one with a highest differential value. 
 
     
     
       17. An apparatus comprising: at least one processor and at least one memory including a computer program, where the at least one memory and the computer program are configured, with the at least one processor, to cause the apparatus to carry out the method of  claim 16 . 
     
     
       18. The apparatus according to  claim 17 , configured to superimpose two or more of the clean images (IMP 1 , IMP 2 , IMP 3  . . . IMPn) together, to obtain an angiogram (A 1 , A 2 ) with a more complete representation of the zone of examination (Z), including multiple immissions of contrast medium. 
     
     
       19. The apparatus according to  claim 17 , configured to approach and join two or more angiograms (A 1 , A 2 ) for obtaining the image of a larger zone of examination (Z). 
     
     
       20. A non-transitory computer readable medium having computer program code stored thereon for execution of the method of  claim 16  by a signal processor.